We are quickly approaching the November 1st deadline when the minimum version requirements for connecting Outlook (on Windows) to Office 365/Microsoft 365 services will change.

After 1 November 2021, only Outlook 2013 Service Pack 1 and newer will be able to connect to Office 365/Microsoft 365 services. Outlook 2007, 2010, and Office 2013 versions earlier than 15.0.4971.1000 are no longer supported by Microsoft, and will stop connecting from this date.

Microsoft is enforcing this blocking of old versions as they are incompatible with upcoming service changes, which include both security and performance improvements (e.g. adding support for HTTP/2).

The solution is to upgrade your version of Office (and thereby Outlook) – Office is available as part of Microsoft 365 or as a standalone purchase of Office 2019.

You can read Microsoft’s full statement here.